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The Rock Cycle

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Sedimentary rocks
Sandstone
Conglomerate
Limestone

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Sedimentary rocks
How sedimentary
rocks are formed:
1) Weathering
2) Transportation
4) Burial
3) Deposition

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Sedimentary rocks

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Metamorphic rocks
Slate
Marble
Quartzite

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Metamorphic rocks
Metamorphic rocks are formed by the combined effect of
heat and pressure on other rocks:
Pressure from rocks above…
…and heat from magma nearby

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Metamorphic rocks

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Igneous rocks
Granite
Pumice
Obsidian

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Igneous rocks
Igneous rocks
are formed
when lava or
magma cools
down and
solidifies
If the lava or magma cools
QUICKLY it has SMALL crystals
If the lava or magma cools
SLOWLY it has BIG crystals

10. 31/03/2014
Crystal sizes in igneous rock
The size of the crystals in igneous rock shows how quickly
the rock had cooled.
SLOW cooling = BIG crystals
FAST cooling = SMALL crystals
e.g. this rock
will cool
____, so the
crystals will
be ____
This rock will cool
_____, so the
crystals will be
_______

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Igneous rocks
Magma
Extrusive
igneous rock
Intrusive
igneous
rock

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Summary
Sedimentary, igneous
or metamorphic?
How they were
formed
Appearance
(e.g. sandstone,
limestone, chalk)
Small pieces of
sediment were stuck
together by salt and
pressure from rocks
above
Usually soft, can
contain fossils, easily
eroded
(e.g. basalt, granite)
Liquid rock (magma or
lava) cooled down and
turned back into a
solid
Contain crystals, very
hard, never contain
fossils
(e.g. marble, slate)
Other rocks were
acted on by heat and
pressure over a long
time
Sometimes have tiny
crystals, no fossils,
always hard and
sometimes arranged
in layers

13. 31/03/2014
The Rock Cycle

14. 31/03/2014
Rocks revision quiz
1. What are the 3 types of rock?
2. What type of rock are the following:
Sandstone, limestone, granite, basalt, slate
3. What type of rock would a mountain probably be made out of?
4. What are the two conditions needed for a metamorphic rock to form?
5. Which metamorphic rock is formed from limestone?
6. Why wouldn’t you find any fossils in igneous or metamorphic rocks?
7. You find a rock containing crystals. What type of rock would it most
probably be?
8. What is molten rock that is inside the Earth called?
9. What is molten rock that is outside the Earth (i.e. erupted) called?

15. 31/03/2014
Rocks revision quiz
10. Name one example of physical weathering.
11. Name one example of biological weathering.
12. Acid rain is an example of chemical weathering. What poisonous gas
(given off by car exhausts and power stations) causes acid rain?
13. Granite is an igneous rock and contains large crystals. Did it cool down
slowly or quickly?
14. In the rock cycle what causes igneous rock to become sedimentary
rock?
15. In the rock cycle again what causes the sedimentary rock to become
metamorphic rock?
16. Gravestones are usually made out of marble or granite instead of
limestone or sandstone. Why?
17. A piece of rock contains layers. What type of rock would it probably
be?